The field of the present disclosure relates to optical time delay apparatus. In particular, optical time delay apparatus are described herein that incorporate diffractive element sets.
One or more distributed optical structures (i.e., sets of diffractive elements) in a channel waveguide, an optical fiber, a slab waveguide, or another guided-wave optical structure may be used in a variety of devices for beam steering, spectral filtering, laser frequency control, spectral multiplexing, optical sensing, optical delay, or other functions. It is often desirable that such devices be optimized, or nearly so, for routing, mapping, or coupling optical signals between input and output optical ports with minimal optical loss. Apparatus incorporating diffractive element sets for providing time-delayed optical signals are described herein. Such time delay apparatus may, for example, function as true-time delay devices which are relevant in the case of phased array radar systems or other applications.
Various embodiments, implementations, and adaptations of such diffractive element sets are disclosed in: application Ser. No. 11/062,109 filed Feb. 17, 2005; pending, application Ser. No. 11/055,559 filed Feb. 9, 2005; now U.S. Pat. No. 7,123,744, application Ser. No. 11/021,549 filed Dec. 23, 2004; pending application Ser. No. 10/998,185 filed Nov. 26, 2004; now U.S. Pat. No. 6,993,223, application Ser. No. 10/989,236 filed Nov. 15, 2004; now U.S. Pat. No. 6,965,716, application Ser. No. 10/898,527 filed Jul. 22, 2004; pending application Ser. No. 10/989,244 filed Nov. 15, 2004; now U.S. Pat. No. 6,961,491, application Ser. No. 10/798,089 filed Mar. 10, 2004 (now U.S. Pat. No. 6,823,115 issued Nov. 23, 2004); application Ser. No. 10/653,876 filed Sep. 2, 2003 (now U.S. Pat. No. 6,829,417 issued Dec. 7, 2004); application Ser. No. 10/602,327 filed Jun. 23, 2003; now U.S. Pat. No. 6,859,318, application Ser. No. 10/229,444 filed Aug. 27, 2002 (now U.S. Pat. No. 6,678,429 issued Jan. 13, 2004); application Ser. No. 09/843,597 filed Apr. 26, 2001; now U.S. Pat. No. 6,965,464, and application Ser. No. 09/811,081 filed Mar. 16, 2001 (now U.S. Pat. No. 6,879,441 issued Apr. 12, 2005). Each of said applications is hereby incorporated by reference as if fully set forth herein.
The following publications are also incorporated by reference as if fully set forth herein: Mossberg, “Planar holographic optical processing devices,” Opt. Lett. 26 414 (2001); Greiner et al., “Lithographically-fabricated planar holographic Bragg reflectors,” J. Lightwave Tech. 22 136 (2004); Greiner et al., “Fourier-transform-limited performance of a lithographically-scribed planar holographic Bragg reflector,” Photon. Technol. Lett. 16 840 (2004); Iazikov et al., “Apodizable integrated filters for coarse WDM and FTTH-type applications,” J. Lightwave Tech. 22 1402 (2004); Mossberg, “Lithographic holography in planar waveguides,” SPIE Holography Newsletter 12 (2001); Iazikov et al., “Effective grayscale in lithographically scribed planar holographic Bragg reflectors,” Appl. Opt. 43 1149 (2004); Boggs et al., “Simple high-coherence rapidly tunable external-cavity diode laser,” Opt. Lett. 23 1906 (1998).